A WINDOWS (registered trademark of Microsoft Corporation in the United States and other countries) operating system (OS) has built therein a database called a system registry (hereinafter, simply referred to as a “registry”) into which setting information of hardware and software is registered. The WINDOWS registry has five root keys and a plurality of subkeys hierarchically associated with each of the root keys. Each end subkey has an entry including a setting name and a setting value described therein.
A computer system can operate normally as various programs read the setting information in the registry when the system is started or while the system is running The registry is updated for example when an application program is installed or uninstalled, when the OS is updated, or when the system environment settings are changed. Further, a user can use a program called a registry editor to customize the registry. The computer system may operate unstably or unexpectedly if a user updates the registry incorrectly or malware tampers with the registry.
In order to restore the functions of the computer system of which operation has become unstable due to a change of the registry, WINDOWS OS uses a system restore application. The system restore application generates snapshots of the entire registry in chronological order, so as to allow the state of the entire registry to be returned to the state at a certain restore point in the past. There also is a method of deleting data that has been tampered by a process registered in a black list, by means of cleanup software or spyware disinfecting software. Japanese Unexamined Patent Publication No. 2005-078628 teaches a system that provides an access to information stored in a registry and dynamically partitions the registry. In the system of the Japanese Unexamined Patent Publication No. 2005-078628, a dynamic partition data store stores redirection information associated with an application and the registry, and in response to a request from the application, it provides information associated with the registry on the basis of the redirection information. Japanese Unexamined Patent Publication No. 7-056719 teaches a method of initializing and updating a registry in order to ensure the boot of a computer.
The above-described method of returning the setting values in the entire registry back to those at the restore point on the basis of the snapshot takes a long time to process. The properly updated entries will also be returned to the previous values, which may impose an inconvenience on a user.